"We intend to release them by June 1," said White House spokeswoman Lindsay Walters in an email to CNN.

The news was first reported late Friday by the New York Times. It comes about a month after Office of Government Ethics director Walter Shaub first asked the White House and federal agencies for the names of anyone who had been granted an exemption from ethics rules.

For example, if an administration official once worked as a lobbyist, an ethics waiver could allow that person to bypass rules restricting the issues he or she can work on.

Shaub has traded letters with President Donald Trump's top budget official over the last two weeks about whether the White House would provide any waivers it has issued.

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Mick Mulvaney, the director of the Office of Management and Budget, asked Shaub last week to stop the inquiry. Shaub fired back on Monday with a letter of his own, insisting that the White House turn over the names by June 1.

"The unusual nature of your letter highlights OGE's responsibility to lead the executive branch ethics program with independence, free from political pressure," Shaub wrote Monday.

Mulvaney wrote back to Shaub on Friday, telling him that the budget office "shares the belief that the executive branch must uphold the highest ethical standards in accordance with the law."

The letter obtained by CNN also refuted Shaub's characterization of Mulvaney's request.

"Contrary to your assertions, OMB has never sought to impede OGE nor to prevent others, including agencies, from acting as required by law," Mulvaney wrote. He added that the budget office did not issue or approve any waivers requested by Shaub's inquiry.

Trump signed an executive order in January that prohibits former lobbyists from participating in anything directly related to their former employers or clients for two years. The order relaxed Obama-era rules that more tightly restricted lobbyists in government.

Because the Trump administration is keeping ethics waivers secret, it's unclear how many have been granted. Outside watchdog groups and Democratic lawmakers have pressed the White House for an answer and encouraged the ethics office to stay on top of it.

Shaub told CNN on Friday that he was "glad to receive" Mulvaney's letter, and said he appreciated that the budget office has "no objection" to his request.

"That will resolve any confusion his earlier letter may have caused for ethics officials and general counsels," Shaub said.